Insulator pins and method of manufacture



Dec. 10, 1963 E, RYAN A 3,114,000

INSULATOR PINS AND METHOD OF MANUFACTURE Filed Aug. 15,v 1960 3 Sheets-Sheet 1 H62 I FI'G.4

- INVENTOR. EDMUND C. RYAN y L STER R.WENDLAND w 10%- groans! Deg. 10, 1963 E. (3. RYAN ETAL 3,114,000

INSULATOR PINS AND METHOD OF MANUFACTURE Filed Aug. 15, 1960 3 Sheets-Sheet 2 FIG. 5

INVENTOR.

ATTORNEY Dec. 10, 1963 0. RYAN ETAL 3,114,000

INSULATOR PINSAND METHOD OF MANUFACTURE FiledAug. 15, 1960 3 Sheets-Sheet 3 INVENTOR.

EDMUND C. RYAN y LEiTER RWWN:

ATTORNEY United States Patent 0 3,l14,lltltl INEEEJEATQR Pl'Nll AND Ill-ETHQD 0F MANUFAKITURE Edmund (Lilly an and Lester R. Wendland, Mansfield,

shoulder so that the sleeve is rigidly held against the @hio, assignors to The @hio Brass Company, Mansfield, 0

Ohio, a corporation of New .lersey Filed Aug. 15, 1968, Ser. No. $5,596 l6 Claims. (Cl. 174-194) This invention relates to pins and sleeves for suspension insulators and to methods and apparatus for the manufacture thereof.

United States Patent 3,076,868 by E. C. Ryan and J. J. Taylor describes an improved suspension insulator in which the pin is shielded by a metal sleeve. The sleeve is disposed about the shank of the pin and extends from adjacent the head of the pin to a point along to simplify and expedite the manufacture thereof. Manufacture of the pin and sleeve has heretofore been difficult and relatively expensive because the known designs and configurations of the pin and sleeve, necessary to obtain the best insulator strength and length of life, lead to manufacturing costs which are high in comparison with manufacturing costs of pins for the usual suspension insulator. The pin and sleeve of the present invention provide a structure of the necessary characteristics at an acceptable manufacturing cost.

The structural arrangement necessary in a pin and sleeve arrangement of the types described in United States Patents 2,443,435 and 3,076,868 are as follows:

first, the sleeve must be rigidly attached to the pin; and secondly, the inward deformation of the sleeve under conditions of corrosive growth should, preferably, be facilitated by corrugation of the sleeve, at least along its outer extremity. The first of these conditions irnposes difiicult manufacturing requirements particularly in the improved insulator of the l. J. Taylor application above referred to wherein a conical sleeve is attached to the pin at its smaller end. Specifically the pin is most economically formed by upsetting or forging operations and the sleeve must be attahced to a shoulder on the pin which is of lesser diameter than the ball or head of the pin.

In accordance with the present invention, the sleeve is formed from a blank constituted by a length of cylindrical metal tubing having an inside diameter greater and radial projections at the shoulder to depressions and ridges at the exterior end of the blank so as to constitute longitudinal corrugations circumferentially arranged at the exterior end of the sleeve. The end of the sleeve abuts the head of the pin at the juncture of the head with the The shoulder of the pin.

The pin and sleeve are cleaned and then galvanized by dipping in molten zinc. The zinc closes all the crevices and apertures between the sleeve and the pin and, additionally, the spaces between the walls of the radial projections of the sleeve. in addition to its function as a protective coating, the zinc serves to bond the sleeve to the pin and the .co-extensive portions of the radial projections of the sleeve to assist in maintaining the compressive engagement of the sleeve with the shoulder of the pin.

The invention will be more fully understood by reference to the following detailed specification and clairns taken in connection with the appended drawings, in

which:

FIG. 1 is a side elevation .view, partly in section and partly broken away, of a suspension insulator illustrating the invention;

FY12 is a side elevation view of the suspension pin and sleeve of the insulator of HG. 1, also partly in section;

FIG. 3 is a section view of the pin and sleeve of FIG. 2 taken along the line 3-3 of FIG. 2;

FlG. 4 is a view, partly in section, of the pin and sleeve of FIG. 2, taken along the line 4 l in FIG. 2;

EH15 is an elevation view of apparatus for automatically forming the sleeve and for assembling the sleeve on the pin, in accordance with the invention;

FIG. 6 is a horizontal section view, partly broken away, taken in the direction 6d in FIG. 5; and

FIGS. 7 to 11, inclusive, show the shape and design of a finger of the die shown in FIG. 5.

Referring now to FlG. 1, there is shown a suspension insulator ltl comprising an insulator body ll, a cap 12, pin 13 and sleeve 14. The insulator body 11 is constituted of a vitreous electrical insulating material, usual porcelain, shaped as a disc 15, a central part or bell 1-6, and skirts on the under part of the disc 15. The cap 12 is secured to the exterior of the bell 16 by a body 17 of Portland cement and a coating l8 constituted by sand particles embedded in a layer of glaze which extends around the exterior of the bell id. The pin 13 and sleeve 14 are held in the open interior of the bell in by a body 19 of Portland cement and a coating 2t? constituted by particles of sand embedded in a layer of glaze which extends peripherally about the interior of the bell. A pad 21 of felted paper extends across the top of the head of the pin 13 and the exterior surface of the head of the pin 13 and the exterior surface of the head is covered with a coat of asphalt for reasons not particularly re lated to the present invention. The cap is formed as a socket 23 atthe outer end thereof and the pin 13 is formed as a ball 24 at the outer end thereof to connect the insulator ill to ancillary suspension and strain apparatus.

The present invention is concerned with the organization of the the pin 13 and the sleeve 14. As is shown in FlG. 2, the pin 13 is constituted by an elongated shank 25 having the ball 24 constituted as an integral enlargement at one end and a head 26 constituted as an integral enlargement at the remaining end thereof. A shoulder 27 is constituted as an integral enlargement of the shank 25, adjacent the head 26, and has a lesser diameter than f the head 24-. The shoulder 27 has a flat conical surface which tapers inwardly in the direction of the head 26 and terminates at the exterior surface 28 of the head 26.

The ball 24, shank 25, head 26 and shoulder 27 are of circular cross-section, being symmetrical about the longitudinal axis of the pin. The exterior surface 28 is constituted with a spherical contour, referred to as a spheroidal surface. The term spheroidal surface, as used herein, denotes any surface having a substantially spherical contour with the center of curvature on the longitudinal axis of the pin or offset therefrom.

. The pin 13 is made conveniently from bar stock by upsetting or forging operations. The opening 3%) is convenient in certain forms of making, but otherwise not a necessary part of the pin. The pin is made of medium carbon or alloy steel although non-ferrous alloys or stainless steel may be used.

The sleeve 14 is constituted of sheet metal and having a generally conical shape and disposition. The sleeve has a plurality of discrete conical segments 31 which conform to and are engaged with the conical outer surface of the shoulder 27 of the pin 13. The conical segments 31 extend throughout the length of the sleeves from one end to the other and are connected by radially extending projections 32 which are formed by folded portions of the sheet material of the sleeve. The radial projections 32 are produced as a result of the forming operation of the sleeve 14, but also function, in part, as a holding means for attaching the sleeve 14 to the shoulder 27.

According to the invention, manufacture of the sleeve in the form shown is accomplished by providing a tubular metal blank constituted by a length of cylindrical metal tubing with an inside diameter greater than the outside diameter of the ball 24, relatively positioning the blank and the pin with the blank over the shank, and forming the blank into the desirable conical shape with the smaller end of the sleeve in engagement with the shoulder 27' while the blank is so positioned. Manufacture is facilitated by use of the apparatus shown in FIGS. and 6.

Referring now to FIGS. 5 and 6, the apparatus therein shown comprises a bottom die 40, a top die 41, a plurality of fingers 42 for holding a sleeve 43, and a receiver 44 for holding a pin 45.

The bottom die 40* includes a base, a generally cylindrical upright 46 having an opening 47 in which the pin 45 is received. The receiver 44 is carried by the body 48 of the top die 41 and slides in an opening 49 against the spring 56. A piece 51 functions as a slide for the receiver 44 as well as a limit stop for the spring Sll. The receiver 44- is normally held in the fullyextended position by the spring 50* and is compressed by engagement with the end of the pin 45 as the dies 40 and 41 aer moved together.

The upright 46 of the bottom die 40 carries the fingers 42 in a plurality of radially extending openings arranged at equally spaced intervals around the part. Each opening extends through the wall of the upright 46 and each of the fingers is received in a circularly shaped depression 52 which conforms to a circular end part of the finger for pivotal movement thereof. Each of the fingers 42 is restrained by an elastic spring 53 which is connected to the upright 46 by a screw 54 and to the finger 42 by a pin 55 (FIG.

The dies 40 and 41 are mounted in a hydraulic press which moves the top die 41 toward the bottom die it in alignment therewith and at the requisite pressures. The fingers 42 areactuated by engagement of an insert 56, carried by the body 48 of the top die 41, with the outer face 57 of each of the fingers 42 along the surface 58 of the insert. The insert 56 is made of hard material, or is suitably face hardened with the faces 57 of the fingers 42, to prevent unduewear of the engaging parts.

Each of the fingers 42 is formed at the lower extremity of the inner face 59 thereof with a projection 65)- which serves to support and hold the sleeve, blank 43. The open position of the fingers 42 is such that the faces 59 extend in parallel directions along the exterior of the blank, so that the projections 61? of the several fingers engage the bottom end of the blank.

Each of the fingers 42 is formed adjacent the top extremity with -a projection 61 from the inner face 59 of the finger. The projection 61 has a front face 62 which is formed as a circular are having a radius equal to that of the outer surface of the sleeve 14 and so disposed that, with the finger 42 in the final position, the face 62 is centered on the longitudinal axis of the pin. Accordingly, during inward movement of the fingers 4-2, the projections e1 force the body of the tubular blank inward into contacting relationship with the exterior surface of the shoulder 27 to form the discrete portions 31 of the sleeve 14.. The intervening portions of the blank are folded between the fingers to constitute the radial projections 32 of the sleeve 14, as is shown in FIG. 6.

The inner faces 56 of the fingers 42 are shaped to form the longitudinally extending convolutions in the blank which constitute, at the outer end of the sleeve 14,- the corrugations shown in FIG. 4. As will be evident from a consideration of H68. 9, l0 and 11, the change in the shape of the finger from the concave face 62 at the pro jection 61 to the convex face 63 to the projection 60', together with the circumferential spacing of the fingers produces in the formed sleeve a gradual transition from the segments 31 (FIG. 3) to the concave convolutions 33 (FIG. 4), and from the radial projections 32 (FIG. 3) to the convex convolutions 34 (FIG. 4).

In manufacture, the tubular blank 43 is placed between the fingers 42 so that the blank rests at its lower end upon the projection 57 of each of the fingers. The pin 45 is then inserted through the blank so that the head of the pin rests upon and is supported by the blank at the upper end of the blank. The inward movement of the fingers 42 as a result of the downward movement of the top die 41 toward the bottom die 40 compresses the blank inward in the radial direction of the movement of several fingers. The inward movement of the blank simultaneously forces the pin 45 in the upward direction, with movement of the inner edge of the blank along the spherical surface (corresponding to the surface 28 of the pin 13) of the head of the pin 45, until the head of the pin engages the receiver 44 The force exerted by the spring 5h, through the receiver 1-4, on the end of the pin, opposes the inward movement of the end of the sleeve 43 such that the inside edges of the end of the blank are in substantial engagement with the pin at the juncture of the exterior surface of the head of the pin with the exterior surface of the shoulder when the inwardly dc formed portions of the tubular blank are in contacting engagement with the conical surface of the shoulder (that is, along the discrete conical portions 31 indicated in FIG. 3). Accordingly, a mechanical joint is formed between the sleeve and the pin as the fingers 42 are brought to a fully closed position (indicated in FIG. 5). The shaping of the blank along the length to produce the convolutions of the sleeve 14 is, of course, accomplished during the inward movement of the fingers 42 as hereto fore described.

Following the assembly operations, the pin and sleeve are galvanized by dipping in a molten zinc bath maintained at a temperature of about 850 degrees F. The molten zinc forms a coating over the exposed surfaces of the pin 13 and the sleeve 14 and makes a smooth joint between the end of the sleeve and the head 26 and between the interior surface of the sleeve and the exposed end face of the shoulder 27. Moreover the zinc penetrates between the co-extending walls of the radial projections 32 to solder those walls together as well as provide a coating over the exterior and end portions of theprojections. The bonding of the co-extending walls of the radial projections 32 tends to prevent loosening of the mechanical joint between the smaller end of the sleeve at the shoulder 27 and and the head 28 because of strain, expansion and contraction, or other forces tending to cause radial enlargement of the sleeve.

The penetration of the molten zinc between the sleeve 14 and the shoulder 27 along the contacting conical surfaces is dependent upon the fit between the inner surface of the sleeve and the conical surface of the shoulder.

With a tight mechanical joint between the sleeve and the shoulder, the penetration is limited and a zinc coating over the entire surface of the pin may be assured by galvanizing the pin before the assembly operation. Ordinarily a sufficient sealing and protective coating of zinc may be achieved in the single galvanizing operation referred to above.

It is to be understood that the principal function of the zinc is as an anti-corrosive coating. However presence of the metal enhances the strength of the interlocking joint between the sleeve and the pin. Thus the metal between the end of the sleeve 14 (indicated at 65 in FIG. 2) and between the inner surface of thesleeve and the open face of the shoulder (indicated at 66 in FIG. 2) have a bonding effect in addition to that accomplished by uniting the co-extending portions of the radial projections 32..

The assembly operations accomplished by the apparatus shown in FIGS. 5 or 6 may be either manually or automatically controlled. Although not entirely essential to the practice of the method, the cylindrical tubular blank may be heated to a temperature of 500 degrees F. prior to the crimping operation. This facilitates the working of the metal of the sleeve of the blank and enables produc tion of assemblies in which the joints between the sleeve and the pin have uniform and consistant characteristics. Again, the lower end of the pin 45 may be supported by a receiver, on the lower die 46, so that the pin is carried between two receivers during the crimping operation. However, greater attention to control of the vertical position of the pin during the crimping operation is required than in the method just described.

In certain circumstances, as for example, with spad end pins, the tubular blank may be flattened slightly in order to pass the blank over the end of the spade and onto the shank of the pin. The blank may thenbe reformed into a cylindrical shape and the blank and pin inserted into the bottom die 4i) together prior to the crimping operation.

The sleeve 14 is preferably made of low carbon or low alloy steel, although the material used is not particularly critical. Some of the considerations in the selection of materials is set forth in United States Patent No. 2,443,- 435 idem.

It is to be understood that the foregoing description is not intended to restrict the scope of the invention and that various rearrangements of theparts and modifications of the design may be resorted to. The following claims are directed to combinations of elements which embody the invention or inventions of this application.

We claim:

1. That method of manufacturing a pin and sleeve assembly which comprises making a metal pin in the form of a shank, a head at one end of the shank, and a shoulder on the shank adjacent the head, the said shoulder having the surface thereof tapered inward in the direction of the head, making a tubular metal blank, positioning the blank over the shank and shoulder, and crimping the blank inward into circumferentially contacting engagement with the shoulder along circumferentially discrete conical segments while imparting a generally conical shape to the blank along the length thereof, to form the blank into a sleeve and a mechanical joint between the sleeve and the pin.

2. The method in accordance with claim 1 in which the pin and the blank are relatively positioned during forming of the sleeve by movement of the end of the sleeve along the surface of the head in the direction of the shoulder.

3. The method in accordance with claim 1 with folding the portions of the tubular blank between the discrete segments thereof into convolutions having closely adjacent radially coextending portions during crimping the blank.

4. The method in accordance with claim 1 in which the sleeve is united with the pin by dipping in molten metal to fill the spaces between the sleeve and the adjacent portions of the shoulder and the head.

5. The method in accordance with claim 3 in which the sleeve and pin are united by dipping in molten metal to fill the spaces between the adjacent portions of the sleeve and pin and between co'extensive portions of the wall of the blank.

6. A pin and sleeve assembly comprising a metal pin in the form'of a shank, a head at one end of the shank,

a shoulder formed as an integral radial enlargement of the shank and adjacent the head, a metal sleeve surrounding the shank with one end thereof abutting the head of the pin and tapered inward and engaged along the interior surface of the sleeve adjacent the said one end with the exterior of the shoulder along discrete circumferential portions thereof.

7. The invention in accordance with claim 6 in which the sleeve, is united with the pin by means comprising a metal coating filling the interstices between the sleeve and the shoulder.

8. A pin and sleeve assembly for a suspension insulator comprising a metal pin in the form of a shank, a ball at one end of the shank and a head at the remaining end of the shank, a shoulder formed integrally with the shank adjacent the head and having the surface thereof tapered inwardly in the direction of the head, a generally conical metal sleeve surrounding the shank with the smaller end thereof engaged along the interior surface of the sleeve with the exterior of the shoulder along discrete circumferential portions thereof and means holding the said sleeve in supporting engagement with the said shoulder.

9. The invention in accordance with claim 8 in which the said holding means comprises an end of the sleeve abutting the head of the pin.

10. The invention in accordance with claim 8 in which a metal coating fills the interstices between the sleeve and the pin.

ll. The invention in accordance with claim 9 with folded intervening portions of the said sleeve between the said discrete circumferential portions.

12. The invention in accordance with claim 8 with longitudinally directed convolutions about the circumference of the sleeve extending from the shoulder engaging portions thereof to the open end of the sleeve.

13. The invention in accordance with claim 11 with longitudinally directed convolutions about the circumference of the sleeve extending from the shoulder engaging portions thereof to the open end of the sleeve and at least some of the said convolutions constituting continuations of the said folded portions of the sleeve.

14. That method of manufacturing a pin and sleeve assembly which comprises first making a pin having a shank, a ball at one end of the shank, a head at the remaining end of the shank and a shoulder on the shank adjacent the head, the said shoulder having the surface thereof tapered inward in the direction of the head and having a lesser diameter than the diameter of the ball, making a tubular metal blank with an inside diameter greater than the inside diameter of the ball, positioning the blank over the shank and shoulder of the pin by relative longitudinal movement of the ball end of the pin coaxially through the blank, and then deforming the tubular blank inward along discrete circumferential segments at one end thereof into contacting engagement with the shoulder and abutting engagement with the adjacent portions of the head while simultaneously folding the portions of the tubular blank between the discrete circumferential segments thereof into. convolutions having closely adjacent radially coextending portions, all to form the tubular blank into a generally conical sleeve and fix the sleeve in coaxial relation concentrically surrounding the pin with the remaining end of the sleeve spaced from the shank of the pin.

15. A pin and sleeve assembly for a suspension insulator comprising a metal pin in the form of a shank, a

ball at one end of the shank, a head at the remaining end of the shank and a shoulder on the shank adjacent the head, the said shoulder having the surface thereof tapered inward in the direction of the head and having a lesser diameter than the diameter of the ball, a generally conical metal sleeve surrounding the shank and having the interior surface of the sleeve engaged with the exterior surface of the shoulder and the sleeve abutting the head, all along discrete circumferential segments at the smaller end of the sleeve, the sleeve being thereby fixed on the pin in coaxial surrounding relation therewith and the remaining end of the sleeve spaced from the shank of the pin.

16. A pin and sleeve assembly in accordance with claim 15 in which the sleeve has outwardly extending convolutions between the discrete circumferential segments which have closely adjacent radially extending portions and constituting a continuous part of the sleeve.

References Cited in the tile of this patent UNITED STATES PATENTS 1,906,829 Acly May 2, 1933 1,994,266 Austin Mar. 12, 1935 1,994,292 Taylor Mar. 12, 1935 2,014,441 Matthews Sept. 15, 1935 2,320,680 Temple June 1, 1940 2,375,574 Metheny et a1. May 8, 1945 2,443,435 Taylor June 15, 1948 

6. A PIN AND SLEEVE ASSEMBLY COMPRISING A METAL PIN IN THE FORM OF A SHANK, A HEAD AT ONE END OF THE SHANK, A SHOULDER FORMED AS AN INTEGRAL RADIAL ENLARGEMENT OF THE SHANK AND ADJACENT THE HEAD, A METAL SLEEVE SURROUNDING THE SHANK WITH ONE END THEREOF ABUTTING THE HEAD OF THE PIN AND TAPERED INWARD AND ENGAGED ALONG THE INTERIOR SURFACE OF THE SLEEVE ADJACENT THE SAID ONE END WITH THE EXTERIOR OF THE SHOULDER ALONG DISCRETE CIRCUMFERENTIAL PORTIONS THEREOF. 